[Drbd-dev] Re: drbd uses wrong API for struct bio

[Jens Axboe]

On Mon, Jan 24 2005, Lars Marowsky-Bree wrote:
> On 2005-01-24T10:10:07, Jens Axboe <axboe at suse.de> wrote:
> 
> > drbd_ee_init() doesn't look good. First of all, it makes assumptions
> > about what bio_init() would do - it doesn't clear the entire bio to 0.
> > This is the type of thing that exposes bugs when we add or change parts
> > of the bio stuff, please uncomment that bio_init() call. It does set
> > bio->bi_max_vecs, however it needs changing to passing the bdev in so we
> > can use bio_add_page() instead. drbd_ee_bio_prepare() looks strange, it
> > sets vec length but doesn't assign the page or offset. Again, it should
> > use the proper api (bio_add_page()). If it had used bio_init(), it would
> > not have to set BIO_UPTODATE manually either.
> 
> I may be missing something here, but the interaction between
> drbd_ee_init() and drbd_ee_bio_prepare() doesn't map neatly to the
> bio_init() + bio_add_page() API. Part of the setup happens in
> _ee_init(), but the other half in _prepare(), so that neither one has
> all information readily available to use the correct bio_*() API.

Yes, that is what would be nice to fix :-)

Make drbd_ee_init() just init the bastard, and add the page in
prepare().

-- 
Jens Axboe